/*
 * Licensed to STRATIO (C) under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership.  The STRATIO (C) licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.stratio.cassandra.lucene.schema.mapping;

import com.stratio.cassandra.lucene.IndexException;
import org.apache.cassandra.db.marshal.*;
import org.apache.commons.lang3.StringUtils;

import java.math.BigDecimal;

/**
 * A {@link Mapper} to map {@link BigDecimal} values. A max number of digits for the integer a decimal parts must be
 * specified.
 *
 * @author Andres de la Pena {@literal <adelapena@stratio.com>}
 */
public class BigDecimalMapper extends KeywordMapper {

    /** The default max number of digits for the integer part. */
    public static final int DEFAULT_INTEGER_DIGITS = 32;

    /** The default max number of digits for the decimal part. */
    public static final int DEFAULT_DECIMAL_DIGITS = 32;

    /** THe numeric base. */
    private static final int BASE = 10;

    /** The max number of digits for the integer part. */
    public final int integerDigits;

    /** The max number of digits for the decimal part. */
    public final int decimalDigits;

    private final BigDecimal complement;

    /**
     * Builds a new {@link BigDecimalMapper} using the specified max number of digits for the integer and decimal
     * parts.
     *
     * @param field the name of the field
     * @param column the name of the column to be mapped
     * @param indexed if the field supports searching
     * @param sorted if the field supports sorting
     * @param validated if the field must be validated
     * @param integerDigits the max number of digits for the integer part, defaults to {@link #DEFAULT_INTEGER_DIGITS}
     * @param decimalDigits The max number of digits for the decimal part, defaults to {@link #DEFAULT_DECIMAL_DIGITS}
     */
    public BigDecimalMapper(String field,
                            String column,
                            Boolean indexed,
                            Boolean sorted,
                            Boolean validated,
                            Integer integerDigits,
                            Integer decimalDigits) {
        super(field,
              column,
              indexed,
              sorted,
              validated,
              ByteType.instance,
              DecimalType.instance,
              DoubleType.instance,
              FloatType.instance,
              IntegerType.instance,
              Int32Type.instance,
              LongType.instance,
              ShortType.instance,
              UTF8Type.instance);

        // Setup integer part mapping
        if (integerDigits != null && integerDigits <= 0) {
            throw new IndexException("Positive integer part digits required");
        }
        this.integerDigits = integerDigits == null ? DEFAULT_INTEGER_DIGITS : integerDigits;

        // Setup decimal part mapping
        if (decimalDigits != null && decimalDigits <= 0) {
            throw new IndexException("Positive decimal part digits required");
        }
        this.decimalDigits = decimalDigits == null ? DEFAULT_DECIMAL_DIGITS : decimalDigits;

        int totalDigits = this.integerDigits + this.decimalDigits;
        BigDecimal divisor = BigDecimal.valueOf(BASE).pow(this.decimalDigits);
        BigDecimal dividend = BigDecimal.valueOf(BASE).pow(totalDigits).subtract(BigDecimal.valueOf(1));
        complement = dividend.divide(divisor);
    }

    /** {@inheritDoc} */
    @Override
    protected String doBase(String name, Object value) {

        // Parse big decimal
        BigDecimal bd;
        try {
            bd = new BigDecimal(value.toString());
        } catch (NumberFormatException e) {
            throw new IndexException("Field '%s' requires a base 10 decimal, but found '%s'", name, value);
        }

        // Split integer and decimal part
        bd = bd.stripTrailingZeros();
        String[] parts = bd.toPlainString().split("\\.");
        validateIntegerPart(name, value, parts);
        validateDecimalPart(name, value, parts);

        BigDecimal complemented = bd.add(complement);
        String bds[] = complemented.toString().split("\\.");
        String integerPart = StringUtils.leftPad(bds[0], integerDigits + 1, '0');
        String decimalPart = bds.length == 2 ? bds[1] : "0";

        return integerPart + "." + decimalPart;
    }

    private void validateIntegerPart(String name, Object value, String[] parts) {
        String integerPart = parts[0];
        if (integerPart.replaceFirst("-", "").length() > integerDigits) {
            throw new IndexException("Field '%s' with value '%s' has more than %d integer digits",
                                     name,
                                     value,
                                     integerDigits);
        }
    }

    private void validateDecimalPart(String name, Object value, String[] parts) {
        String decimalPart = parts.length == 1 ? "0" : parts[1];
        if (decimalPart.length() > decimalDigits) {
            throw new IndexException("Field '%s' with value '%s' has more than %d decimal digits",
                                     name,
                                     value,
                                     decimalDigits);
        }
    }

    /** {@inheritDoc} */
    @Override
    public String toString() {
        return toStringHelper(this).add("integerDigits", integerDigits).add("decimalDigits", decimalDigits).toString();
    }

}
